This is an excellent example of statistics that give you a good idea, but hide the most important thing (just like a mini skirt).
My (subjective) interpretation of these stats is that Mignolet is pretty much a good keeper, who has one significant flaw that he needs to work on, the one that's recognized by all (and not his distribution). The comparison with Begovic and Pepe from last season stats gives another part of the truth - the failed claims. The stats are small, but this is something that a good keeper cannot afford to do. Once committed to a punch/catch, you have to make it. That can be learned with experience. If Mignolet works to improve that aspect of his game, which also comes with "commanding the box", he'd be a much better keeper and we'd be set for a long time.